I’m not sure why it worked previously, but it’s definitely a theme conflict that is messing up the display. I see this frequently with users who are using complex themes and/or frameworks.

I could get in touch Pagelines and see if they have a fix or a compatibility plugin that will make the theme play nice with bbPress. I’m sure you are not the first person who is using the framework to have this problem.

As a Genesis Framework user, people who use Genesis + bbPress have problems very similar to this, which is why I developed the bbPress Genesis Extend plugin which makes them play nice. Pagelines needs to do something along these lines as well.